Tuesday, September 19, 2006

Science in the media sausage grinder

Recent weeks have offered a rich harvest of new "health" threats with splashy headlines warning us about the supposed dangers from processed meats, hair dyes, and tanning parlors. While all of these stories are all a little odd, perhaps the oddest is the one about how meat increases the risk of stomach cancer. This story was featured on the networks and in several major papers. One news outlet even went so far as to tell its readers just how much bacon they could eat before being at risk for cancer!

What makes the meat and stomach cancer story odd from the get-go is the fact that compared to the rest of the world, North America has one of the lowest rates of stomach cancer incidence and mortality in the world at 10 per 100,000. The highest rates are found in Latin America, Asia and Eastern Europe. And the pattern of declining incidence found here is repeated throughout much of the Western world.

But the really peculiar thing about the meat and stomach cancer scare is how fundamentally at odds the news reports were from the actual science. Back in the Spring the Journal of National Cancer Institute in the United States published a study on meat intake and the risk of stomach and esophageal cancer by a research team led by Carlos Gonzalez of the Catalan Institute of Oncology in Barcelona, "Meat Intake and Risk of Stomach and Esophageal Adenocarcinoma Within the European Prospective Into Cancer and Nutrition". The researchers looked at cancer and nutrition involving some 520,000 Europeans for over six years. According to Gonzalez, there was an increased risk of stomach cancer associated with total meat intake, red meat intake and processed meat consumption. But a mere 330 subjects developed stomach cancer, and in those most at risk of developing it -- those over 60 -- the absolute risk of developing it over 10 years was 0.33% for the heaviest meat eaters groups versus 0.26% for the near vegetarian crowd. Where's the epidemic, and the big difference?

But then came another study, "Processed Meat Consumption and Stomach Cancer Risk: A Meta-Analysis," by Susanna Larsson from the Karolinska Institute in Stockholm. Larsson conducted a meta-analysis of 15 previous studies on the relationship between processed meat consumption -- including bacon, sausage, hot dogs, salami, ham and various smoked meats -- and stomach cancer risk that were published between 1966 and 2006. She found that "increased consumption of processed meat is associated with an increased risk of stomach cancer."

The world media dutifully reported this frightening news, scaring people off their BLTs and sausage at breakfast, and no doubt saving many a pig's life. Only the conclusion was compromised. To start, only seven of the 19 studies included in the study had results that were statistically significant. Of the seven studies linking bacon and stomach cancer -- the headline grabber -- only two were statistically significant; while of the nine regarding sausage only three had statistical significance. And to top it off, Larsson's own study of processed meat and cancer, which she included in the meta-analysis, showed no statistically increased risk of stomach cancer associated with eating bacon, sausage and hot dogs, and ham and salami.

The studies that were statistically significant reported relative risks that were so small as to be indistinguishable from chance. For example, the relative risks for stomach cancer from an increase in processed meat consumption of 30g a day was 1.38, where relative risks below 2 are considered not to indicate a causal connection. Even eating ham, which had the highest reported risk, had a relative risk of only 1.64.

Meanwhile, contradicting Larsson's metaanalysis was an enormous prospective study, "A Prospective Study of Diet and Stomach Cancer Mortality in United States Men and Women" in 2001 done by the American Cancer Society. It involved 436,000 Americans and found no increased risk of stomach cancer associated with eating processed meats. That study, during 14 years of follow-up, documented 439 stomach cancer deaths in women and 910 in men. It found that: "none of the food groups examined were associated with risk of stomach cancer except for an unexpected increased risk with vegetable consumption in women."

Why hasn't anyone warned women not to eat their veggies? It would have been ridiculous, of course, just as it is now to exaggerate dangers from processed meat. All of this highlights a major flaw in the way in which the media covers food and health stories that was pointed out recently by the International Food Information Council's Food for Thought, a report on how the media reports on food issues. According to the IFIC, there were more than 3,000 assertions of harm or benefit of some food based on a scientific study in news stories in 11 leading North American newspapers in 2005. Yet only 2% mentioned whether the study found a statistically significant connection between something like the food and the disease. In other words, whether the connection was real or not was never reported in the overwhelming majority of the stories. With reporting like that, we can be assured of a continued run of headlines warning that bacon causes stomach cancer and ... whatever. Let the pigs rejoice.


New diabetes drug: "A drug that makes the body more sensitive to insulin can help to prevent patients developing diabetes, scientists say. An international trial has found that taking the drug rosiglitazone can reduce the chance of people getting type 2 diabetes by up to two thirds among those at high risk. Type 2 diabetes is strongly associated with obesity and is increasing on the scale of a global epidemic. It is diagnosed in more than 5 per cent of all adults, accounting for 85 to 95 per cent of all diabetes cases, and this rate is rising rapidly throughout the world. In addition, about 300 million people worldwide are estimated to have an impaired ability to regulate their use of glucose, a condition sometimes referred to as “pre-diabetes”, which puts them at especially high risk of developing the disease."

Bread good for you again: "Trying to lose weight by giving up your daily bread? You could be losing out on a whole lot of nutrition if you do. The anti-carb brigade has carved bread up a bit lately, but people who shun a slice are missing out on essential nutrients in a delicious and simple form. Bread is a perfectly packaged source of protein, fibre and complex carbohydrates, and is still one of the simplest lunch options around. Let's face it; the options for fillings you can use are virtually limitless. "Bread's a great source of nutrients because the grains themselves contain a lot of nutrients," says dietitian Alison Miles. Miles says that for optimum health we need to make sure we eat a wide range of foods from all the food groups, and plenty of research is stacking up to say that weneed to include more wholegrains."


Just some problems with the "Obesity" war:

1). It tries to impose behavior change on everybody -- when most of those targeted are not obese and hence have no reason to change their behaviour. It is a form of punishing the innocent and the guilty alike. (It is also typical of Leftist thinking: Scorning the individual and capable of dealing with large groups only).

2). The longevity research all leads to the conclusion that it is people of MIDDLING weight who live longest -- not slim people. So the "epidemic" of obesity is in fact largely an "epidemic" of living longer.

3). It is total calorie intake that makes you fat -- not where you get your calories. Policies that attack only the source of the calories (e.g. "junk food") without addressing total calorie intake are hence pissing into the wind. People involuntarily deprived of their preferred calorie intake from one source are highly likely to seek and find their calories elsewhere.

4). So-called junk food is perfectly nutritious. A big Mac meal comprises meat, bread, salad and potatoes -- which is a mainstream Western diet. If that is bad then we are all in big trouble.

5). Food warriors demonize salt and fat. But we need a daily salt intake to counter salt-loss through perspiration and the research shows that people on salt-restricted diets die SOONER. And Eskimos eat huge amounts of fat with no apparent ill-effects. And the average home-cooked roast dinner has LOTS of fat. Will we ban roast dinners?

6). The foods restricted are often no more calorific than those permitted -- such as milk and fruit-juice drinks.

7). Tendency to weight is mostly genetic and is therefore not readily susceptible to voluntary behaviour change.


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